Data transfer networks include network devices such as, for example, Internet Protocol routers and data transfer links connecting the network devices to each other. Concerning, for example, data transfer networks employing the Internet Protocol “IP”, there are several methods to configure host network addresses, i.e. host IP-addresses, but much less means are provided to router interface network address, i.e. interface IP-address, configuration. Commonly in IPv4 “Internet Protocol—version 4” enabled networks, hosts have their changing network addresses through the Dynamic Host Configuration Protocol “DHCP” during boot-up. Routers have usually statically allocated permanent network addresses from global or non-global address blocks. The IPv6 “Internet Protocol—version 6” and its neighbor discovery schema “NEIGHD” allow auto-configuration with Router Solicitation and Router Advertisement messages which can be used to auto-configure host IPv6-addresses. Nevertheless, routers of an IPv6-data transfer network are not included in the auto-configuration framework and the additions of IPv6-address auto-configuration “ADDRCONF” and the above-mentioned Neighbor Discovery scheme do not remove the complexity of configuring routers in an IPv6-data transfer network. Furthermore, for the purpose of protection and/or load sharing between different data transfer links of a data transfer network, there is many times a need to configure the routing and forwarding databases of routers or other network devices so that there are two or more alternative data transfer paths between the routers or other network devices under consideration.
Publication US2008259925 discloses a method for delegating Internet Protocol network address-prefixes between routers that are connected with data transfer links to each other so as to constitute a hierarchical logical arrangement. The method comprises detecting, by a router, a first router advertisement message received from another router situated at a higher level of the hierarchical logical arrangement. The first router advertisement message is arranged to specify a first network address-prefix owned by the other router and usable for address auto-configuration in the router. The router can perform recursive network address-prefix delegation and assign a sub-portion of the first network address-prefix to other routers situated at a lower level of the hierarchical logical arrangement. Hence, the routers can automatically obtain delegated network address-prefixes from received router advertisement messages specifying prefix delegation information options. However, the method does not provide tools for arranging parallel data transfer paths between separate routers or other network devices.